Giant double whirlpools in the ocean and the DIY ones you can make in your pool

How much don’t we know?

Giant pairs of whirlpools travel across the ocean for months in a bizarre pair.

These large paired whirlpools, hundreds of kilometers across, travel eastward at something like 10-20cm per second. This is one pair crossing from Tasmania to NewZealand. This was there in our satellite data but “invisible” til recently. As David Evans says “I wonder what else we are observing but not seeing?”

The pair of whirlpools called Modon E travelling eastward from Tasmania to NZ.

The ocean becomes connected at two distant points as the Modon-E whirlpool pair travels from Tasmania to NZ in 2010-2011

In the mini-pool version, these rolling whirlpools are connected in a U shape under water.

Wow. PhysicsGirl shows how to make these by pushing a plate through the water, and adding food coloring. Switch on your science nerd, show the kids! (send me your photos :- ))

The two vortexes spin in opposite directions but are connected as a pair underwater. This was created by PhysicsGirl using a plate in a pool and two different food colorings.

Twin giant ocean whirlpools travel for months winding their way across oceans

For the first time, scientists have recorded a bizarre phenomenon in fluid dynamics, which up until now had only ever been theoretically predicted, but never observed in the wild.

“Ocean eddies almost always head to the west, but by pairing up they can move to the east and travel ten times as fast as a normal eddy, so they carry water in unusual directions across the ocean,” explains oceanographer Chris Hughes from the University of Liverpool in the UK.

“What we found was a pair of eddies spinning in opposite directions and linked to each other so that they travel together all the way across the Tasman Sea, taking six months to do it.”

Since 1993, satellites have recorded nine of these pairs (called Modons). Eight of nine that have been found were around Australia. (Perhaps Australian-NZ oceanography is special, but I suspect other modons just haven’t been identified yet). From the paper:

The nine modons we have identified are probably the clearest. There is no sharp cutoff to what could be considered a modon, and there are many other temporary associations of pairs of vortices, particularly to the southwest and south of Australia, and in the region of formation of Agulhas ring eddies. There are hints of acomplex eddy regime in the Pacific off the southern tip of South America, but the relatively small amplitudes and length scales here make interpretation ambiguous. There may also be brief pairings in the Gulf of Alaska and eddies shed from the southern tip of Madagascar certainly interact (de Ruijter et al., 2005, 2004), but clear evidence of modons is not seen. Movies showing modon propagation are given in the supporting information of this paper.

h/t to David E

Watch Physics Girl do some extremely cool pool tricks.

I’ve seen 99% of the hands-on science tricks out there but this was totally new to me. Oogle away. The twin vortices leave pairs of shadows on the pool floor. They travel right across the pool, but vanish sometimes unpredictably, or are destroyed easily by any interference.

….

Notice the red ink whirlpool reaches over and envelops the blue one. The colors stay separate.

You can think of an ocean eddy as something like an underwater tornado with two ends. The swirling water is sped along the twisting vortex, pushing it from one spot in the ocean to another. They’re a well documented natural phenomenon, and serve to regulate temperatures and transport nutrients over large distances, but fast-moving twin eddies put a new spin on what scientists thought they already knew.

Researchers were able to observe the odd ocean behavior using satellite data to measure the depth at which the eddies took shape as well as the speed of the water within them. The flowing water acts like a two-lane highway, moving in both directions simultaneously.

For any small sea creatures not capable of escaping the vortex, the ride can be a long one.

….

We’re not sure how they are formed. From the paper:

From our data it is difficult to determine the formation mechanism. Precursor eddies are rarely distinguishable, though for the Tasman Sea modons the anticyclonic vortex can sometimes be seen propagating down theAustralian coast for some time before pairing up with an opposite vortex in the vicinity of Tasmania, which is reminiscent of the Southwick et al. (2015) mechanism, though it should be noted that there is significant variation in the position at which pairing occurs. It is quite striking in the animations how rapid the initial propagation can be after pairing, giving the appearance of a jet squirting out from the coast before settling into a modon form. For the open ocean cases it is even less common to see precursor eddies, but the many monopolar eddies in these regions suggest that a chance pairing of two complementary vortices is likely in these regions. If anything, it is surprising that we only have one example in the Atlantic sector, given how

energetic the Agulhas region is.

Never too old to get excited. :- )

REFERENCE

Hughes, C and Miller, P (2017) Rapid Water Transport by Long-Lasting Modon Eddy Pairs in the Southern Midlatitude Oceans, Geographical Research Letters, 44, PDF in full

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Rating: 9.1/10 (43 votes cast)

Giant double whirlpools in the ocean and the DIY ones you can make in your pool, 9.1 out of 10 based on 43 ratings

Had another attack of mental diarrhea? Obviously, Craig, you’re a walking, talking, encyclopaedic suppository carrying the complete knowledge of the waka hourua, and everything to do with sailing it, from the shipcraft, through the Navigation methods, how to find land from the wave shapes and swell behaviour, and especially all about the hazards they faced and coped with.

Well?
Are you going to enlighten us all?
We’re waiting on you … but not holding our breath …

And it’s Physics Girl, not Science Girl.
For that you get the Flower of the Week Award! (A Pansy )

Obviously it’s an attempt by Russians in collusion with the Trump Administration to disrupt commercial fishing in the Tasman Sea at the behest of the Big Fishstick Cartel. I have a dossier on this for sale now that I’ve retired from MI7 (we go MI6 one better). By the way, didn’t David Evans get it bassackwards? Shouldn’t he have said, “I wonder what else we are seeing and not observing?”

Tradition has it that he accepted a copper coin, like the Hellenic obolos, or later a danake, for the crossing. The tradition, even to quite recently, was to place the `ferryman’s fare’ as a coin in the mouth of the deceased.

The video of Physics Girl’s demonstration was excellent.
In the field of instrumentation we use vorticies to measure flow. There are many excellent YouTube videos on the topic. A general explanation is here: https://karlgaff.wordpress.com/karman-vortex-streets/
My thoughts on this post are as follows:
Vorticies may be formed when a solid body is placed in a flow path (water or gas). You can see this when you look a a river and underwater logs form eddies.
Now ocean currents can be slow but the energy contained is vast. I understand that a current flows down the east coast of Australia and another along the south coast and the two meet on the eastern side of Tasmania.
These two ocean currents are near the top of the list for their length and power and the amount of water flowing in them.
I do not know if these two currents meeting would form a double whirlpool however there may be an additional influence.
The ocean current flowing along Australia’s south coast also flows around Tasmania. That is, there is flow along the south of Tasmania and the north through Bass Strait. The northern current is special because the water mass must travel between the mainland and Tasmania where the depth is about 50 metres.
The water depth of the Bight is as much as 4000 metres so when the sea bed changes from 4 kilometres to 50 metres the water must speed up creating a high flow intersecting the eastern seaboard south flowing current.
My thought is that this high flow intersecting current may form an effect like the Physics Girl’s plate causing the two ocean currents to form a double whirlpool.
It may also be that Tasmainia itself acts like a block body causing or assisting the whirlpool formations.

I read somewhere not all that long ago, and did not note the source, which I now regret, about massive long-lived eddies or whirlpools in the sea, well away from land. It said something about the ocean having its own internal analogs to atmospheric weather.

‘A seafloor array of recorders spanning the Tasman Sea has measured the electric field signature of a major warm-core ring embedded in the East Australian Current. Theory for motional electromagnetic induction allows the electric measurements to be interpreted in terms of barotropic water velocity. Water transport and kinetic energy estimates thus obtained show a concentration of mesoscale activity near the Australian coast. The total circulation of the particular ring is estimated to be of the order of 100 Sv.’

I wanted to run out to the pool and try this, but it’s currently frozen solid with an outside temperature of -14C. I did notice that the pool she used doesn’t appear to be operational. The circulation pump looked to be off and the water condition was poor. I’m assuming that the normal pool circulation would kill of the vortex pretty quickly. Something to play with when it gets a bit warmer.

What I saw in the pool demonstration would seem to be the same thing pilots call wing tip vortices. I’m left wondering if a similar joining up happens in the atmosphere behind a big jet and we can’t see it. I can’t even think of an experiment that would make it visible. You can’t just drop a little food coloring in the vortex behind that jet as it lifts off at roughly 150 knots when the vortex is strongest.

It’s an interesting world we live in.

As a guess — I know the vortex behind each wing tip spreads out behind the plane and I wonder if they meet, bump into each other at some point and rotating in opposite directions, can manage to join up and reinforce each other. I know the vortex pair behind a big jet flying at low speed can linger for a long time, sometimes as much as 5 minutes before it’s dissipated completely.

I often watch planes landing. In just the right conditions, the airflow over the top of the wing creates instant condensation at various points over the wing and at the wing tip.
The reason very little vortical activity is visible is design: you definitely do *not* want vortices forming when you are going for aerodynamic efficiency.

The vortices I’m talking about happen at the wingtip and are a result of air pressure being higher on the bottom of the wing than it is on the top. That’s why the wing generates lift. The wingtip is a place where nothing prevents air from moving from bottom to top and so it does. Instant vortex and they’re created whether they can be seen or not. Those little vertical fins you see on the newer planes are to prevent that airflow. However, they’re only partially effective and the vortex still happens. It’s just reduced in magnitude. Their net benefit is that you get more lift from the same wing and airspeed.

Those vortices are a real hazard to smaller aircraft and have caused more than one crash when a single engine pilot landed too close behind a big jet. If you get into it it will roll you uncontrollably.

Some of the shots in David Maddison’s link show exactly what I’m talking about. When flying into a cloud the vortex on each side can be seen to spread out and they appear to be doing roughly what the demo in the pool is showing.

I’ve often wondered if interrupting the flow in a manner similar to that used by humpback whales acts by creating a destructive waveform where the multiple vortexes peaks and troughs cancel each other out.

maybe someone could push a frilly edged plate through a pool and see. I suspect ruffles would work similarly to a wavey edge.

Actually he’s correct. You really don’t want the wingtip vortices because they represent a danger to following aircraft and they reduce the lift you could otherwise get from the same wing. And eliminating the vortices is what those little winglets are all about on the newer jets. They don’t completely eliminate the vortex but it’s reduced a lot and by doing that you gain quite a bit more lift from the same wing design and size. The reason is very simple, the winglet maintains a higher pressure differential between the bottom and top areas of the last few feet of the wing and that pressure differential is what lifts the plane. More pressure differential equals more lift.

Craig appears to mistake the condensation over the top of the wing for a vortex, which it isn’t but it is evidence that the pressure is lowered on top of the wing and that is exactly what the designer does want. No pressure reduction over the top surface would mean no lift and no flight.

Actually you don’t really want that “flutter” as one of his links describes it. But physics is what it is. And just think, if not for that phenomenon such beautiful and versatile instruments as the flute, clarinet and oboe would be impossible. Those instruments are specifically designed to crate that flutter at audible frequencies but the airplane designer would rather be without that little artifact if he could eliminate it. I flew a plane for a while with a NASA designed wing that apparently did reduce that flutter effect.

Any airplane will pull 2 g at a 60° bank angle in level flight. That’s the FAA regulation limit for intentional turns except in an emergency. If you could see the additional pressure differential under those conditions it might scare you witless. The airplane itself has to be able to withstand much more than that because turbulence can be completely unpredictable. If I remember plus 6 g and negative 4 g is the design requirement. However, I think the manufacturer only needs to demonstrate safety at some lower figure. Pushing the design limit is not very sensible while several thousand feet in the air.

It all came about because someone finally investigated the shape of bird wings and tried to duplicate that. They were successful and the glider was born.

Bernoulli’s principle was well known and a light bulb lit up and guess what? Two bicycle mechanics from Dayton Ohio decided to try for powered flight. They succeeded and the rest, as they say, is history. They had both flown gliders and were well familiar with how they worked and all they really did was scale up their machines from what they knew best, the gliders thay had flown in the past. But that was their ultimate downfall because it led them to a completely impractical design and it took Glen Curtiss to make flying practical.

The wrights were impressive anateur engineers and scientists, even designing a wind tunnel to test propeller designs. But I doubt that they ever knew anything about wingtip vortices.

The most math they would have needed was to compute weight and balance and compare that with the lift and control authority their first unpowered airplane could generate. Once they had those numbers mastered they had their Kitty Hawk flight in 1903 firmly in their hands.

into the the video as the planes enter the clouds. They appear to join up just a few seconds behind the plane. Whether this is actually the same thing Jo is talking about or not is something for greater experts than I am.

There is a difference between the condensation seen forming on top of the wing and a vortex. On top of the wing the pressure drops rapidly as air is forced to move faster over the longer path to arrive at the rear edge of the wing — Bernoulli’s Principle at work — and according to the same gas laws that are obeyed anywhere else, reducing the pressure causes cooling and when there’s enough humidity, water droplets condense and become visible.

Some colored smokes, thick “oily” long-lasting smokes, vivid in hue, on the tips of the wings might make for a spectacular effect. I’m sure someone has done that, or at least considered it. And with nanobot tech coming along, it might be really cool to incorporate a few into the stream for, um, measurement and science, yeah. For science. Not because it would look cool.

Yes. The wing tip vortices join above the ground behind the runway where the airplane became airborne – in ideal conditions. In true world the vortices lose energy, spread up, and join tens of kilometers behind the airplane in very diffuse way.

I’m glad to read that something beside bad ideas is immortal. I was beginning to think climate change would be lonely as it goes on into the future. But now I can breathe easier knowing it will have company to talk to; company that’s certainly better accounted for by real evidence than climate change has to offer.

Well, what did you expect? It’s the end of one year and the beginning of another. There’s cause to celebrate and make merry, not be serious. We have a brand new opportunity to get right the things we got wrong in 2017. I say that’s cause to laugh and celebrate.

It took roughly forty years for Piltdown Man to be killed off. It was the radio carbon dating in 1953 which finally exposed it as the hoax it was.

It’s going to take the incoming ‘Littler Ice Age’ over the next three decades to lay AGW in its grave, and, because of the computer models, and the UN’s backing, even that’s not going to be final. I can see it sputtering along for a while yet.

The end of the Piltdown hoax was the final proof, but belief in it had been fading for years.
Much the same applies to the Global Warming hoax with belief fading as shown by the unwillingness of the general public to spend anything on it. It is the politicians and more importantly the bureaucrats who see advantages (for them) in throwing money away on it.
Whether some of the gullible believers will ever recognise its falsity is doubtful, they are likely to be delusional until their death, but the “cause” will die as far as public policy goes. That latter point should require a new set of politicians and a cleanout in the top ranks of bureaucracy, but both sets are adept at changing rhetoric and covering up the past and will try that to retain positions.
I have started rereading David Archibald’s Twilight of Abundance; I don’t agree with some of what he says but he does highlight the seriousness of the coming bout of global cooling. If you haven’t read it I suggest it as (depressing) reading.https://www.amazon.com.au/Twilight-Abundance-Century-Nasty-Brutish/dp/1621571580/ref=sr_1_1?ie=UTF8&qid=1514756178&sr=8-1&keywords=David+Archibald

The Tasman sea is contrarian in general.
High tides on the west coast of New Zealand happen during low tides on the east coast.
In the transitional bits, like on the far south coast, you have to be careful which town’s tidal charts you refer to.

30 Dec: IllawarraMercury(Fairfax): Wollongong marine biologist ‘surprised’ some clownfish have no personality
by Agron Latifi
Most species of anemonefish (including Amphiprion ocellaris, made famous by the movie Finding Nemo) live in tropical waters and in previous laboratory studies have been shown to exhibit personality traits.
But scientists have found while the anemonefish from Lord Howe Island, which live in a shallow, sheltered lagoon, were found to have distinct personalities, those from the deeper, more exposed waters at North Solitary Island lacked personality…

The paper’s lead author, marine biologist Dr Marian Wong from the University of Wollongong’s Centre for Sustainable Ecosystems Solutions, said there wasn’t enough variation between the A. latezonatus at North Solitary Island anemonefish to say the species exhibits personality traits…
Fellow researcher Dr Anna Scott added one of the key behaviours scientists looked at was how individuals measured on the boldness-shyness continuum…

The paper, “Some anemonefish lack personality: a comparative assessment of behavioural variation and repeatability in relation to environmental and social factors” (LINK), is published in Coral Reefs.

‘Hughes and Miller noted that double whirlpools stayed together for six months and traveled at long distances of more than 1,000 kilometers before they split up. They move 10 times faster than an average whirlpool but are capable of traveling toward the east, a direction that is not commonly taken by eddies.

‘The researchers have also found that modons are made of waters with different content. A double whirlpool spotted in the Tasman Sea carried water with deep oxygen content as well as high salinity value.’

I read once about a current that moved up the West coast of the USA and Canada to a point where it became so cold an hence denser. The increased density allowed it to descend into the abyss where it displaced large volumes of water.

These subsurface currents involve massive quantities of water and energy and may involve hundreds of years in a cycle before resurfacing. This is the source of the energy that allows the vortices to activate.

Apart from an awareness of the roaring forties, that’s all I know about ocean movement.

I read once about a current that moved up the West coast of the USA and Canada to a point where it became so cold an hence denser. The increased density allowed it to descend into the abyss where it displaced large volumes of water.

These subsurface currents involve massive quantities of water and energy and may involve hundreds of years in a cycle before resurfacing. This is the source of the energy that allows the vortices to activate.

Apart from an awareness of the roaring forties, that’s all I know about ocean movement.

The oceans RULE the climate, and the sun feeds the oceans with energy.

There is a LOT of system buffering/lag, which we have yet to fully figure out (but it seems Dr Evans may be on the right path).

Over the last half of last century, we had a solid series of strong solar cycles, some called a “Grand Solar Maximum”. That is what is responsible for the strong El Ninos that have caused the warming steps and transients in the satellite data.

That has now passed, and it seems we may be heading into a protracted period of lower solar activity.

Exactly how long until this starts to produce cooling is the real question of interest.

I surmise that the 2015/16 EL Nino was actual a balancing release of energy from the oceans.

If so, then over the next year or so, we will start to see a gradual drop in the global temperature (in UAH, anyway.. going to take a lot of cooling to get passed the data fudging in other temperature series.)

Time will tell.

The sooner the better from the world perspective, because a strong cooling trend would destroy the anti-CO2 agenda, which is the REAL threat to modern civilisation and its future.

Countries would be forced to reinstate reliable, solid, despatchable energy sources, as so called renewables, wind and solar, proved unable to supply as required.

One really interesting point in Zharkova’s paper is an alternative explanation for the Sporer Minimum, claiming it was not a Solar Minimum, but Cosmic Ray storms from a super novae. [Tycho Brahe's and Kepler's Stars IIRC] That would mean the Oort, Wolf, Maunder and Dalton Minima were Solar driven, as will be the upcoming one.

The Sun is spotless again. I’m almost tempted to say “as usual” but there was a sun spot which appeared on the 19-20th December last year, and has now rotated away without any excitement. If the present activity (no sunspots) is the sign of things to come, then the TC season will be very quiet. [Fingers Crossed!] However, it takes only one active sunspot (hissy and spitty) to upset the apple cart.

The current ‘X Factor’ Solar-induced Orbital Wet/Normal Cycle has just reached Australia’s East Coast, after starting around 110 degrees East longitude,(Beijing) circa mid-February 2017 and travelling East to West around the planet with the Earth’s Solar Orbit.(This is what has caused the recent extreme cold and precipitation events in Europe and North America,) It will take a month to move across Australia and completely displace the incumbent ‘X Factor’ Dry Cycle. A new One Earth/Solar Year Dry Cycle will initiate over 110 degrees longitude circa mid-February 2018.
As prevailing weather moves from West to East,(Axial Spin,) there are opposing forces at work, thus the tendency for large scale opposing vortices to occur in the oceans and the atmosphere.
Alex S Gaddes includes a section on Vortices in his work ‘Tomorrow’s Weather’(1990). In this work he describes and predicts the ‘X Factor’ Cycles, providing their exact terrestrial footprint.
An updated version of this work,(including ‘X Factor’ Cycle forecasts to 2055,) is available as a free pdf from dongaddes93@gmail.com

Dueling vortices attempting to annihilate each other are likely to be of more than academic interest for the wind industry.
“Wind rights and access to natural wind flow raise important legal
issues, policy questions, opportunities, and financial risks for
landowners, their neighbors, and for wind facility developers. This is
particularly evident with respect to the phenomenon called wake
effect (downwind effect) that occurs between commercial upwind
turbines and downwind turbines.” https://scholarship.law.duke.edu/cgi/viewcontent.cgi?article=1192&context=delpf

It does make sense – the plate she uses creates the vortex under water as well as on the surface.

I’d like to see some form of IR photo of the air above the pool (in an enclosed lab) and I bet there would be a circular vortex (air plus water) that breaks apart quickly due to the different mediums… allowing for the hand holding the plate, of course.

The movement is a semi-circular front through the water… it’s not surprising that a semi-circular vortex was created.

But – what creates the connected vortex in the oceans? What mechanism takes the place of the plate? Ha!

Hi Physics girl. I like your vortices. How about creating vortex/antivortex pairs and see how they annihilate when brought together/ Also what happens when vortices collide – thinking about recent black hole gravity wave phenomena observed